CAPE CANAVERAL, Fla., June 10 (UPI) -- Fifty years after Apollo 11 astronauts were first to walk on the moon, the United States and the world are celebrating the historic achievement, while many also lament that moon missions ended decades ago.
The 50th anniversary recalls the spirit and riveting fascination of that first moon mission. Some 600 million people around the globe are believed to have watched the first moonwalk on television -- mostly in black and white, on an 18-inch screen.
The July 20 anniversary also highlights the brief, often politically doomed, attempts to mount another moon mission over the last few decades. And it has put a spotlight on NASA's plan under the Trump administration to launch the Artemis program -- named for the twin sister of Apollo in Greek mythology.
For many, like Apollo astronaut Al Worden, the fact that no one has returned to the moon since 1972 is a harsh and unfortunate reality.
"This anniversary reminds me that there was a time when this country could do great things," said Worden, 87, who orbited the moon as Command Module pilot for Apollo 15, which launched July 26, 1971.
"We had a president who set the tone, explained it and got the resources. We have not had that type of leadership since then," Worden said.
He and many others believe that space ultimately will save humanity as the population and problems grow on Earth.
"We know we can't live here forever," Worden said. "The success of Apollo reminds us that as Americans, if we get together and work together, we can do incredible, impossible things."
Recalling the success of the Apollo program is nothing short of mind-blowing for Regina Spellman and Ken Poimboeuf.
They are working on retooling Pad 39B at Kennedy Space Center in Florida, where Apollo 10 launched, to handle new missions to the moon. NASA has a goal of returning people to the moon by 2024.
Poimboeuf, 76, is a contractor who also worked as an electrical engineer at the space center during the Apollo era, including the Apollo 11 mission.
"I was awestruck by Apollo 11," said Poimboeuf, who works for Millennium Engineering and Integration. "People were all saying, 'I can't believe we're really doing this.'"
Spellman is NASA's senior project manager on the pad renovations. She said her job makes her think every day about the challenges the Apollo program overcame.
"They started with a clean slate. Without that ability to stand on the shoulders of the giants that came before us, things would be much more difficult," Spellman said.
Still there are new unknowns, she said.
"By establishing a sustainable presence on the moon, we're not going to know what to expect because no one has ever done that," she said. "We've got a brand-new launch vehicle also, the space launch system."
With the planned Artemis moon missions, the space launch system would include an SLS rocket, the largest since Apollo's Saturn V, and an Orion capsule.
Any talk about Apollo history, or of returning to the moon, must include the sobering truth about putting people in space: Accidents -- even fatalities -- can and do occur.
Robert Sieck, a NASA retiree and former shuttle launch director, recalls the horrific fire that killed three astronauts during an Apollo 1 launch test.
The fire on Jan. 27, 1967, swept through the command module, killing Roger Chaffee, Ed White and Gus Grissom. The Apollo program was put on hold more than 18 months and underwent major redesign. That accident is now studied, along with the in-flight explosions of the shuttles Challenger and Columbia, in NASA's Lessons Learned program.
Sieck, 80, had been in a neighboring control room at the space center that day and left work an hour before the fire. Like millions of Americans, he watched it on TV.
"Having known the astronauts involved, there was grief and shock. As an engineer, we had to learn from that," Sieck said. He called the eventual Apollo success "a great example of the teamwork" of thousands of people.
"It didn't feel like work. We enjoyed what we were doing," he said. "The stress did have an impact on families, though. It was rewarding work, but only the strong survived."
Sieck said he never thought it would be decades before astronauts returned to the moon or even ventured on to Mars.
"But we came this far, let's keep going," he said.
Moving forward, NASA's Lessons Learned program is key to preventing further tragedy, while all acknowledge that it is impossible to remove risk from space exploration.
Michael Ciannilli, who manages the program, said the key lessons focus on human behavior and group dynamics, such as heading off complacency in established programs and getting personnel to speak up about problems and listening to them.
Some are critical of NASA's new efforts to go to the moon. NASA Administrator Jim Bridenstine has said repeatedly that the biggest obstacle is political, not technical.
Worden said he has seen nothing but Apollo ideas with slight variations and updates in the space agency. He also said that new space companies SpaceX and Blue Origin seem to have a big leg up on NASA.
"In my mind, we've sort of lost the inventive edge we had, because we really just sort of are building the same thing we did 50 years ago," Worden said. "SLS is a repeat of the Saturn V. It's a big rocket, but it's pretty much the same construction of Saturn V. The Orion is just another Apollo spacecraft that's a little bigger."
Talk of going to Mars is largely speculation, he said, because the spacecraft required doesn't exist.
"The shuttle and space station are significant, but we need to go beyond Earth orbit," Worden said.
Bob Cabana, director of Kennedy Space Center, took on critics in recent comments to the media.
"I've heard people say, 'China just landed on the far side of the moon. How did we fall so far behind after Apollo?'" Cabana said. "Well, we've also landed on the far side -- of Mars. That was a pretty fantastic accomplishment. We also were just flying to an asteroid. And flying by Ultima Thule beyond Pluto."
Cabana, 70, is a former space shuttle astronaut. He said he wants to do things that inspire a new generation.
"I'm part of the Apollo Generation. I got to see Apollo 13 launch. That planted a seed. ... I thought maybe I could do that," Cabana said. "But we want to establish the Artemis Generation."